Head for liquid explosives

ABSTRACT

A head for liquid explosives primarily intended for rock destruction having channels for the delivery of liquid components and initiator wherein one of the channels for delivering liquid components and the channel for delivering the initiator converge to form a common outlet channel within the head, and wherein the supply of the liquid components is continuous while the supply of initiator is effected in pulses.

uuucu DLGLCB' l'altilll Inventor Miron Abramovich Schegolevsky Moscow, Drovyanaya Ploschad, 9/10, kv.60, U.S.S.R.

Appl. No. 738,358

Filed June 19, 1968 Patented Apr. 20, 1971 HEAD FOR LIQUID EXPLOSIVES 2 Claims, 3 Drawing Figs.

U.S. Cl l75/4.5, 175/11, 299/13, 299/14 Int. Cl ..E21c 21/00, E21c 37/12 Field of Search 175/2, 4.5,

11; 299/13; 431/91; 102/(Inquired), 22, 23

[56] References Cited UNITED STATES PATENTS 3,106,238 10/1963 Bruce 431/91X FOREIGN PATENTS 122,107 1964 U.S.S.R. 299/13 Primary ExaminerErnest R. Purser Attorney-Waters, Roditi, Schwartz & Nissen PATENTED APR'20197I SHEET 2 [IF 2 The present invention relates to blasting machines employing liquid explosive materials having for their components fuel and an oxidizer fired as a mixture under the action of liquid initiator.

Used as an oxidizer can be nitrogen tetroxide, nitric acid, tetranitromethane, as a fuel-kerosene, benzine, aniline, toluene, and as an initiator there can be used an eutectic alloy of potassium and sodium, and hydrazine.

The apparatus of that type are known as jet-type blasting machines. which can be used for destruction of rocks, for explosive forming under a layer of liquid in open dies and in other fields of engineering where energy of blast can be used.

From the earlier publications, particularly from the USSR Authors Certificate No. l22,l07, there is known a blasting apparatus using liquid explosive and liquid initiator, said apparatus being intended for boring holes. The apparatus is provided with a head having inlet channels for separate delivery of explosive components and liquid initiator supplied to the liquid explosive for its detonation.

The reservoirs for liquid explosive components and initiator are arranged in the apparatus body above the head with channels, and the batching of liquid components and initiator in this case is performed with the aid of valves provided at the inlet end of the channels, said valves being fixed to a springloaded crossbeam. When the portions of liquid explosive are fired one by one, the shock wave forces out the crossbeam with the valves and, through clearances appearing after the displacement of valves, subsequent portions of explosive components and of initiator are delivered via channels to the hole face wherein the mixing of components and their firing under the action of the initiator take place.

The channels for delivery of components and of liquid initiator in the known apparatus are isolated from each other, thereby affecting the operation of the blasting apparatus due to the following reason.

It has been found out that a liquid initiator, in particular eutectic alloy of potassium and sodium when contacting the air or water available in the air and some components of explosive material, namely, nitrobenzene, forms hard slags which clog the portion of channel for delivery of initiator narrowing at the outlet, and the firing process stops. Due to this fact, the known apparatus could find no industrial application.

An object of the invention is to develop an improved blasting apparatus with such an arrangement of channels in the head as to prevent the liquid initiator from direct contact with water or air.

Said and other objects of the invention may be accomplished in a blasting apparatus using liquid explosives, having a head with channels for delivery of explosive components and initiator, wherein, according to the invention, at least one of said channels for delivery of explosive components and the channel for delivery of the initiator converge upon a common outlet channel inside the head.

The present engineering solution of the problem makes it possible to avoid the forming of slags in the most narrowing portion of the channel by way of delivering the initiator into oxidizer or fuel, since, in this case, the outlet orifice of the channel for delivery of the initiator is washed by a component.

Experiments have shown that all components of explosive material, except nitrobenzene, can be successfully used as the initiator protective medium.

The invention will further be described by way of example with reference to the accompanying drawings, in which:

FIG. 1 is a schematic diagram of the blasting apparatus according to the invention;

FIG. 2 shows the head of the blasting apparatus according to the invention; and

FIG. 3 is a partial view on arrow A of FIG. 2. Referring to FIG. 1, the blasting apparatus comprises reservoirs l and 2 for fuel and oxidizer, which are the components of liquid explosive, and reservoir 3 for liquid initiator, said reservoirs being respectively connected by pipelines 4, 5 and 6 with apparatus head 7. Fuel and oxidizer are delivered to head 7 by pumps 8 and 9, while the initiator is delivered under the pressure of compressed air available in receiver 10 connected with reservoir 3.

Head 7 is provided with channels l1, l2 and 13 (FIG. 2) connected to pipelines 4, 5 and 6, said channels serving for delivery of fuel, oxidizer and initiator; oxidizer and fuel in this case flow continuously, while the initiator for firing the charge is delivered periodically.

In case of batch feeding of the components and the initiator use is made of controllable valves, the component-batching valves (not shown in the drawings) being arranged either directly in channels 11 and 12 or in pipelines 4 and 5, while initiator-batching valve 14 is mounted in channel 13. Valve 14 is provided with bushing 15 having an orifice 16 as an inlet and an orifice 17 as an outlet for the initiator, wherein outlet orifice 17 can be closed by needle-type cutoff member 18 traveling in bushing 15 under the action of drive 19.

Orifice 17 has a negligible diameter, which is necessary to form a compact jet of initiator and to eject it with a sufficient velocity, due to which fact slags may appear in said orifice. In order, to prevent orifice 17 from being clogged with slag, channel 12 for delivery of fuel is connected below bushing 15 with channel 20 via which fuel and the initiator flow simultaneously. The initiator in this case is delivered into a jet of fuel washing outlet orifice 17 of bushing 15, the fuel outflow velocity sharply increasing here owing to narrowing of the working cross section of channel 20, while particles of slag being formed are effectively washed out. The particles of slag accumulated inside the orifice 17 are pushed out mechanically by the needle of the cutoff member 18 each time'the valve 14 operates.

In order to avoid the ingress of fuel into the hollow of bushing 15, the operation time of valve 14 should be shorter than the time passing from the moment of injecting the initiatorto the blast.

Channel 11 for delivery of oxidizer comes out into circular recess 21 from which a number of channels 22 (FIG. 3) emerge positioned around channel 20. Such an arrangement of channels 22 facilitate the uniform mixing of the charge of the explosive mixture, which is important, e.g. when boring holes, since the destruction of rocks will take place over the whole area of hole face.

It is advisable sometimes to connect channel 11 with channel 13 and to isolate channel 12 from channel 13.

In order to protect valve 14 from the action of shock waves appearing during the explosion, provision is made for shock absorber 23 made as an elastic gasket pressed between the body of head 7 and bushing 15.

Iclaim:

l. A blasting apparatus adapted for using liquid explosives, mainly for destruction of rocks, comprising a head provided with channels for delivery of explosive components and a channel for delivery of a liquid initiator; one of said channels for delivery of explosive components and said channel for delivery of initiator converging upon one common outlet channel inside said head and said common outlet channel and the other of said channels for delivery of explosive components opening from the head proximate one another.

2. A blasting apparatus as claimed in claim 1 wherein the explosive components are oxidizer and fuel and the initiator is mixed with one of said components in said common outlet channel whereby clogging of said common outlet channel is prevented. 

1. A blasting apparatus adapted for using liquid explosives, mainly for destruction of rocks, comprising a head provided with channels for delivery of explosive components and a channel for delivery of a liquid initiator; one of said channels for delivery of explosive components and said channel for delivery of initiator converging upon one common outlet channel inside said head and said common outlet channel and the other of said channels for delivery of explosive components opening from the head proximate one another.
 2. A blasting apparatus as claimed in claim 1 wherein the explosive components are oxidizer and fuel and the initiator is mixed with one of said components in said common outlet channel whereby clogging of said common outlet channel is prevented. 